Low aqueous solubility is the major problem encountered with formulation development of new chemical entities as well as for the generic development. These amounts resulted in the prediction of higher oral absorption with normal gastric pH than with high gastric pH. Bases "Zn(OH)"_2 is a sparingly soluble base. Decreasing the pH increases the solubility of sparingly soluble bases and basic salts. Many sparingly soluble compounds have solubilities that depend on pH. Published reports have clearly shown that weakly basic drugs which have low solubility at high pH could have impaired absorption in patients with high gastric pH thus leading to reduced and variable bioavailability. The pH of a specific solution is much likely has an impressive effect on solubility. DCF, IDM, and MLX also showed increasing drug solubility. Based on the results, the phosphate ion was demonstrated to affect drug solubility and KTP or IBP solubility increased with increasing phosphate buffer concentration. Drug solubility was measured in different concentrations of phosphate buffer. On the other hand, when diclofenac sodium, the salt form of an acidic drug, was applied to the D/P system with the gastric phase, its dissolved and permeated amounts were significantly lower than those without the gastric phase. Solubility, the phenomenon of dissolution of solute in solvent to give a homogenous system, is one of the important parameters to achieve desired concentration of drug in systemic circulation for desired (anticipated) pharmacological response. Solubility of a weakly basic drug increases with a decrease in the pH below its basic pK a and that of a weakly acidic increases with an increase in pH beyond its acidic pK a [8, 22]. What is the solubility of benzylpenicillin G at a pH sufficiently low to allow only the non-dissociated form of the drug to be present? The objective of this study was to investigate the pH-dependent solubility and dissolution of weakly basic Biopharmaceutical Classification Systems (BCS) class II drugs, characterized by low solubility and high permeability, using carvedilol, a weak base with a pK a value of 7.8, as a model drug. > Increasing the pH has the opposite effect. The importance of solubility in drug research important molecular property that influences the intestinal ... ¾the common-ion effect below pH 2 is significant even in case It all involves the application of Le Châtelier's Principle. Here are two common examples. But it is still needed to classify strong acids from the other. Solubility-pH profile of drugs. Example 4.2 Calculation of the effect of pH on the solubility of an acidic drug. The pK a of benzylpenicillin G is 2.76 and the solubility of the drug at pH …